1. Field of the Invention
The present invention relates to the general field of Liquid Crystal Displays, and more specially to a method of increasing viewing angle and response speeds on a two-domain Chiral Homeotropic LCD with negative compensator.
2. Description of the Prior Art
Currently, the market for LCDs is increasing rapidly. However, the viewing angle and contrast ratio of LCDs are still insufficient for their use in large screen products. For high image quality, these characteristics need to be improved. The Fujitsu Ltd. has proposed a vertical-alignment-mode LCD, recently. Please see the referencexe2x80x9dK. Ohmuro, S. Kataoka, T. Sasaki, Y. Koike SID""97 DIGEST p845xcx9cp848xe2x80x9d. The VA-LCD(vertically aligned LCD) has been implemented by optimizing a vertically aligned mode with a domain-divided structure and an optical compensator. This vertical-alignment-mode LCD has a wide viewing angle of over 70xc2x0, a fast response( less than 25 ms), and a high contrast ratio of over 300, but it still remains some problems. There are disadvantages, for example, the formation of two domain structure by using mask and rubbing process are complex and expensive, the rubbing process also produce ESD(Electrostatic Damage) and particles, further a mask rubbing will result image sticking.
It is an object of the present invention to solve the aforementioned problems. Another objection of this invention is to provide a method of increasing the viewing angle and response speeds on a two-domain Chiral Homeotropic LCD with negative compensator without a rubbing treatment.
These objects have been achieved by forming a two-domain vertical aligned mode LCD. Further, let the liquid crystal molecules in each of the liquid crystal domains are orientated nearly perpendicular to surfaces of the substrates with a little pre-tilted angle to the normal of the substrates when an electric field is not applied, the tilt angle projected on the azimuthal of substrate between the orientation of liquid crystal molecules in two domains are not equal to 180 degree.
To achieve the aforementioned liquid crystal molecules conditions, there are two methods can be provided. One is using an oblique incident linear polarized ultraviolet light beam process with mask shift to expose the orientation layer twice and forming two-domain structure. Another is using two linear polarized ultraviolet light beam incidents from different direction and a fixed mask to expose the orientation layer in the same time.
These methods can increase the response speed of the liquid crystal molecules and provide a rapid and clean process to avoid the disadvantages that mentioned in the background.